In 1990, the mean ph. level of rain in town was 4.61. A biologist fears the ph. level has recently increased. She draws a sample of 13 rain dates and obtains this data:
4.8, 4.3, 4.1, 4.6, 5.1, 4.4, 4.8, 4.7, 4.4, 4.3, 4.3, 4.5, 4.7
Test the biologist'a fear at the 0.01 level of significance